Spectrally sensitized silver halide photographic emulsion

ABSTRACT

A silver halide photographic emulsion containing a supersensitizing combination of at least one carbocyanine dye having a heterocyclic necleus comprising a benzothiazole or benzoselenazole nucleus, at least one of the heterocyclic nuclei having an acetylamino group at the 5-position thereof, and having a sensitized maximum portion within the range of from 600 to 660 nm, and at least one sensitizing dye of the following general formula (II)   wherein R3 and R4 each represents a lower alkyl group; A2 represents a lower alkyl group or an aryl group; Z3 and Z4 each represents an atomic group necessary to complete a benzothiazole, benzoselenazole or Beta -naphthothiazole nucleus; X2 represents an anion; and m is 0 or 1, m being 0 when an intermolecular salt is formed.

United States Patent [1 1 Shiba et al.

[ 1 Nov. 6, 1973 SPECTRALLY SENSITIZED SILVER HALIDE PHOTOGRAPHIC EMULSION [75] Inventors: Keisuke Shiba; l-laruo Takei; Akira Sato; Tadashi lkeda, all of Kanagawa, Japan [73] Assignee: Fuji Photo Film Co., Ltd.,

Kanagawa, Japan [22] Filed: Sept. 24, 1971 [2]] Appl. No.: 183,492

[30] Foreign Application Priority Data Primary ExaminerJ. Travis Brown Attorney-Richard C. Sughrue et al.

[57] ABSTRACT A silver halide photographic emulsion containing a supersensitizing combination of at least one carbocyanine dye having a heterocyclic necleus comprising a benzothiazole or benzoselenazole nucleus, at least one of the heterocyclic nuclei having an acetylamino group at the 5-position thereof, and having a sensitized maximum portion within the range of from 600 to 660 nm, and at least one sensitizing dye of the following general formula (ll)' wherein R and R each represents a lower alkyl group; A represents a lower alkyl group or an aryl group; Z and Z each represents an atomic group necessary to complete a benzothiazole, benzoselenazole or B-naphthothiazole nucleus; X represents an anion; and m is 0 or 1, m being 0 when an intermolecular salt is formed.

5 Claims, 4 Drawing Figures PMENIEmwv 6 ma 3,770,4 9

3s 40 44 4s 52 56 so 64 68 72 WAVE LENGTH (x IOnm) 64 WAVE LENGTH (x lOnm) FIGS I WAVE LENGTH (x l0 nm H64 36 40 44 48 52 56 60 64 68 T2 WAVE LENGTH (x lOnm) SPECTRALLY SENSITIZED SILVER I-IALIDE PHOTOGRAPI'IIC EMULSION BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a spectrally sensitized silver halide photographic emulsion and more especially to a silver halide photographic emulsion which is supersensitized by the combined use of at least two sensitizing dyes resulting in a high red sensitivity.

2. Description of the Prior art Photographic light sensitive materials which are used conventionallyare required to have spectral sensitivity distributions corresponding to the photographing purpose.

In the manufacture of the sensitive material, it is an important technique to develop the combination of sensitizing dyes which are in supersensitization relation to each other and have a small inherent desensitization, Le, a less desensitization, in the wavelength region inherent to silver halide grains.

The object of this invention is to provide a silver halide photographic emulsion having a panchromatically sensitized region, particularly a high red sensitivity within the spectrosensitized wavelength region of 640-685 nm and a small inherent desensitization by the combined use of two different types of sensitizing dyes.

A panchromatically sensitized region is used generally for black and white photographic sensitive materials.

SUMMARY OF THE INVENTION The object of this invention has been accomplished by the combined use of a carbocyanine dye comprising heretocyclic nuclei selected from benzothiazole and benzoselenazole nuclei, at least one of the heterocyclic nuclei having an acetylamino group at the 5-position thereof, and having a sensitized maximum portion within the range of from 600 to 660 nm., preferably of the following general formula (I), and a sensitizing dye of the general formula (II) in a silver halide photographic emulsion:

wherein R l and R, each represents a lower alkyl group, e.g., methyl, ethyl, 'y-sulfopropyl, 'y-sulfobutyl, 6-sulfobutyl, allyl etc.; A represents a lower alkyl group, e.g., methyl, ethyl etc.; 2 represents an atomic group necessary to complete a benzothiazole or benzoselenazole nucleus, which may be substituted by a halogen atom, e.g., chlorine, etc., a lower alkyl group, e.g., methyl, ethyl, etc.; an alkoxyl group, e.g., methoxy, ethoxy, etc.; or a phenyl group; Z represents a sulfur or selenium atom; X; represents an anion, e.g., a chloride, bromide, iodide, perchlorate, p-toluene sulfonate, benzene sulfonate, thiocyanate, methyl sulfate or ethyl sulfate ion, etc.; n is 0 or I and n 0 for the intermolecular salt;

wherein R and R each represents lower alkyl, e.g. methyl, ethyl, 'y-sulfopropyl, 'y-sulfobutyl, 8-sulfobutyl, B-hydroxyalkyl, B-carboxyalkyl, etc.; A represents lower alkyl, e.g. methyl, ethyl, etc., or an aryl group, e.g. phenyl; Z and Z each represents an atomic group necessary to complete a benzothiazole, benzoselenazole or B-naphthothiazole nucleus, which maybe sub-- stituted by a halogen, e.g. chlorine or bromine, etc., a lower alkyl group, e.g. methyl, ethyl, etc.; alkoxy, e.g. m'ethoxy, ethoxy etc.; a hydroxyl group or a phenyl group; X represents an anion, e.g., a chloride, bromide. iodide, p-toluene sulfonate or benzenesulfonate ion, etc. and those used generally in the art; m is 0 or 1 and m=0 for the intermolecular salt.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1-4 are spectograms illustrating the supersensitization effects of the combination of dyes according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Many cyanine dyes of the general formula (II) have a sharp sensitized maximum portion and a high red sensitivity.

The combined use of the sensitizing dyes according to this invention provides a silver halide emulsion having a higher red sensitivity compared to the use of each sensitizing dye alone and, at the same time, a very small inherent desensitization.

It is also possible to use at the same time another sensitizing dye for improving the .green sensitivity (e.g., 2,2-cyanine, thia* 2 -cyani ne etc.) or those having other s jE ctral sensitizing wavelength regions.

The embodiments of sensitizing dyes used in this invention are mentioned as follows, but the sensitizing dyes used in this invention are not to be restricted only to those examples.

Dye 6.

The carbocyanine dyes and sensitizing dyes of the general formula (II) which are used in this invention can be synthesized by a known method. For example, with reference to US. Pat. No. 2,503,776 and German Pat. Nos. 929,080 and 1,072,765, those skilled in the art can readily synthesize them. I

The synthesis of a typical sensitiiin'g' dye of the general formula (I) is described as follows:

Synthesis Dye C One grom of 5-chlor0-3-(y-sulf0propyl)-2- thioFr-opionyl-methylenebenzothiazoline is reacted with 1 g of methyl p-toluene sulfonate at 65 C for 2 hrs and then treated with ethyl ether to yield a methyl thiocarbinol compound. 1.1 g of S-acetylamino- 3-ethyl-2-methylbenzothiazolium p-toluene sulfonate salt are added thereto, and dissolved in ml of ethanol, 2 ml of further triethylamine are added and the whole is heated for 3 hrs under reflux. After the completion of reaction, the solvent is distilled off and treated with ethyl ether and then with acetone to yield coarse crystals of Dye C. The coarse crystals are recrystallized from a mixed solvent of chloroform/ methanol to yield 550 mg of Dye C having a meltingpoint above 310 C and a k of 559 nm. Other sensitizing dyes can be obtained by a similar method to the process as mentioned above.

The physical values of typical embodiments of said carbocyanine dyes according to this invention are as follows:

M1. (C) A I A 300 566 l B 300 554 l C 300 559 l D 276 565 l E 300 560.5 I F 282 562 l G 296.5 562 l H 231 567 l l 300 558.5

The sensitizing dyes of the general formula (I) are used, in general.

tion is effective for the spectral sensitization of any silver halide photographic emulsions. And, it can sensitize sufiiciently an emulsion containing a hydrophilic colloid other than gelatin, for example, agar collodion, water soluble cellulose derivatives, polyvinyl alcohol and other synthetic or natural hydrophilic polymers. For the photographic emulsion used in this invention, a mixed silver halide emulsion such as silver iodobromide, chloroiodobromide, and the like is suitable.

For the preparation of spectrally sensitized photographic emulsions according to this invention, it is enough to add the sensitizing dyes to a photographic emulsion in a common manner. In practice, it is convenient to add the dyes as a solution thereof in a suitable solvent such as methanol, ethanol, cellosolve etc., to the emulsion. The mol ratio of the sensitizing dyes according to this invention to be contained in the emulsion may be varied within a wide range of from 9:1 to 1:9 corresponding to the effect desired.

The photographic emulsion according to this invention may be treated by a known method for hyperand The spectral sensitizing process according to this invenother super-sensitization. In the preparation of photographic emulsions according to this invention, additives 'which are generally used in the art of photographic EXAMPLES Sensitizing dyes used in this invention as mentioned above were added individually to a silver iodobromide emulsion (Agl AgBr =7:93 in mol percent to prepare silver halide photographic emulsions. On the other hand, silver halide photographic emulsions containing a combination of the sensitizing dyes of this invention were also prepared.

These emulsions were coated onto a cellulose triacetate film base, dried, exposed through a red filter (transmitting rays of a wavelength longer than 580 nm) and a blue filter (transmitting rays of a wavelength of 400 490 nm and having a maximum transmission at,

450 nm) to a daylight of 64 Luxes (corresponding to 5,400 K) and developed.

As the developer, one having the following composition was used.

TABLE 1 Metol 2 g sodium sulfite 100 g Hydroquinone 5 g Borax 2 g Water to make 1000 ml.

The relative red .sensitivity and inherent desensitization to the original emulsion for the single use of the sensiziting dyes as well as in the combined use of said sensitizing dyes according to this invention are shown in the following Table 2.

.TABkEZ.

Amount of Amount of sensitizing Senfiilizing Sensitized myse s l added' mu EX erimental Dyg (10' mol/kg Dye (10 mol/kg wave length Relative red Inherent Referred to 1&6. Example No. Flo. emuLsi n No. emulsion) Emulsion (nm) sensitivity sensitivityv in drawings A 4 AgBr/l 656 12s 94 Fig.3(8). A 8 AgBr/l 656 I30 85 AgBr/l 648 9O AgBr/l 650 78 90 AgBr/l 654 l 00 90 l AgBr/l 660 I20 AgBr/l 656 170 94 AgBr/l 656 l85 94 4 AgBr/l 656 I85 94 AgBr/I 600 5 87 Fig. 347 2 AgBr/l 600 6 80 AgBr/l 654 135 90 Fig. 3(9).

AgBr/l 648 I00 AgBr/l 648 I25 I87 AgBr/I 648 I40 87 AgBr/l 662 50 93 3 AgBr/l 662 I00 90 3 C 4 2 1 AgBr/I 654 94 C 4 2 ,535. 3!!! .9, 199, 94

TABLE 2. -Continued Amount of Amount of sensitizing sensitizing Sensitized dye added dye added maximum Experimental Dye mol/kg Dye (10 mol/kg wave length Relative red Inherent Referred to No. emulsion) Emulsion (nm) sensitivity sensitivity in drawings Example No. No. emulsion) No.

. AgBr/l 666 10 90 AgBr/l 634 13 87 AgBr/l 634 26 87 4 1 AgBr/I 652 120 96 AgBr/I 660 135 96 AgBr/l 600 16 1 93 Fi .,2(41. AgBr/l 600 313 93 5 AgBr/l 632 60 85 Fig. 2(5).

AgBr/l 632 110 93 Fig. 2(6).

AgBr/l 640 96 AgBr/l 640 36 90 AgBr/I 640 36 s0 6 AgBr/l 660 1 I0 62 AgBr/l 648 145 90 AgBr/l 648 145 90 A ar/1 642 145 90 AgBr/l 648 36 94 7 AgBr/l 650 62 94 AgBr/l 650 100 94 AgBr/l 648 170 94 AgBr/l 650 I80 94 AgBr/l 600 92 AgBr/l 630 90 11 AgBr/l 630 115 AgBr/l 650 175 94 AgBr/I 650 I80 94 AgBr/l 630 100 Fig. 1 1). AgBr/l 640 150 so AgBr/l 685 73 96 Fig. 1(2). 9 AgBr/l 686 146 96 AgBr/l 686 1511 117 9 11 4 0.5 AgBr/l 680 120 96 Fig. 1(3) H 4 7 1 AgBr/l 682 170 96 AgBr/l 665 50 AgBr/I 665 100 10 AgBr/l 665 95 AgBr/l 665 86 AgBr/l 660 l 96 AgBr/l 646 85 95 Fig. 41101. AgBr/I 664 105 95 11 2 AgBr/l 638 75 110 4 AgBr/l 640 85 70 Fig. 411111 8 AgBr/l 640 85 60 4 B 642 130 100 Fi .4 12 4 451 94. .1

1 AgBr/l 680 35 90 12 2 AgBr/l 680 70 11s 4 AgBr/l 680 120 70 1 AgB'r/I 670 150 90 2 AgBr/l 676 170 90 13 4 AgBr/l 640 I80 106 14 1 AgBr/I 652 195 100 2 AgBr/l 650 50 94 4 AgBr/l 654 90 92 15 6 AgBr/l 658 .130 92 2 AgBr/l 652 .94 4 AgBr/l 658 175 94 2 AgBr/l 1 600 I 20 92 4 AgBr/l 626 48 90 8 AgBr/I 626 75 x5 16 c 4 12 2 AgBr/l 646 150 94 16 c 4 12 4 AgBr/l 646 165 92 The red sensitivity is shown as a relative sensitivity tivity is shown as a relative sensitivity assuming that the assuming that the red sensitivity of sensitizing dye l,exsensitivity of the original emulsion which is exposed posed through a red filter (a filter transmitting rays of 65 through a blue filter (a filter transmitting rays of from a wavelength longer than 580 nm) in an amount of 4 400 to 490 nm and having a maximum transmission at X 10- mol/kg emulsion is 100; and the inherent sensi- 450 nm) is 100.

As is obvious from Table 2, the addition of a single sensitizing dye according to this invention reduces inherent sensitivity together with an increase of red sensitivity as the amount of dye added is increased. However, it is seen that the combined use of the sensitizing dyes provides a higher red sensitivity than in the single use of the corresponding sensitizing dye alone. As is also obvious from examples 13 and l4 in Table 2, the effect of the combination of said sensitizing dyes is not injured by the further addition of a green sensitizing l0 dye thereto, e.g. the combined use of green sensitizing dye (i) or (ii) with the combination of the sensitizing dyes according to this invention.

The said green sensitizing dyes have the following chemical structures, but they are not restricted only to these sensitizing dyes.

CH N

Dye ll wherein R and R each represents a lower alkyl group; A, represents a lower alkyl group or an aryl group; 2;, and Z each represents an atomic group necessary to complete a benzothiazole, benzoselenazole or B naph-. thothiazole nucleus; X, represents an anion; and m is Qorbmkei wh an szrmv ssql saltisf tmcd- 2. The silver halide photographic emulsion of claim 1 wherein the carbocyanine dye is represented by the following generalformula (I) Zi -Zi A! f -cu=l:-cn= 3 NHCOCH;

I N R H R I (lit) n wherein R and R, each represents a lower alkyl group;

A represents a lower alkyl group; z rep res ents an atomic group necessary to complete a benzothiazole or benzoselenazole nucleus; Z represents a sulfur or a selemum atom; X 1- represents an anion, and n is 0 or 1,

n, b e i r g 0 when an intermolecular salt is formed.

3. The silver halide photographic emulsion of claim 1 further containing at least one green sensitizing cyanine dye selected from the group consisting of 2,2- yan1ne and thia-2 -c yanine 4. The silver halide photographic emulsion of claim 1 wherein said carbocyanine dye is selected from the group consisting of Dye 11 s s can -on=h-c1r= emo zmcocm I|-I N and Dye 1.

Dyu 1 s s S C s c 11 -u o01[= CH=JJCH= NIIC0CH 5 N N N N ((inmsoa (L211, i i (HmSoa y S. The silver halide photographic emulsion of claim 2)a aH z s)s 1, wherein said sensitizing dye is selected from the D 8 group consisting of ye 03 S (Hah s zh l Dye 10.

Dye 3. 

2. The silver halide photographic emulsion of claim 1 wherein the carbocyanine dye is represented by the following general formula (I) :
 3. The silver halide photographic emulsion of claim 1 further containing at least one green sensitizing cyanine dye selected from the group consisting of 2,2''-cyanine and thia-2''-cyanine.
 4. The silver halide photographic emulsion of claim 1 wherein said carbocyanine dye is selected from the group consisting of
 5. The silver halide photographic emulsion of claim 1, wherein said sensitizing dye is selected from the group consisting of 